package org.smart4j.chapter2.helper;

import org.apache.commons.dbcp2.BasicDataSource;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;
import org.apache.commons.dbutils.handlers.MapListHandler;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.smart4j.chapter2.util.CollectionUtil;
import org.smart4j.chapter2.util.PropsUtil;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.*;

/**
 * Created by LIJ on 2018/6/13.
 */
public final class DatabaseHelper {
    private static final Logger LOGGER = LoggerFactory.getLogger(DatabaseHelper.class);
    private static final QueryRunner QUERY_RUNNER;
    private static final ThreadLocal<Connection> CONNECTION_HOLDER;
    private static final BasicDataSource DATA_SOURCE;
    static {
        QUERY_RUNNER = new QueryRunner();
        CONNECTION_HOLDER = new ThreadLocal<Connection>();

        Properties prps = PropsUtil.loadProps("config.properties");
        String driver = prps.getProperty("jdbc.driver");
        String url = prps.getProperty("jdbc.url");
        String username = prps.getProperty("jdbc.username");
        String password = prps.getProperty("jdbc.password");

        DATA_SOURCE = new BasicDataSource();
        DATA_SOURCE.setDriverClassName(driver);
        DATA_SOURCE.setUrl(url);
        DATA_SOURCE.setUsername(username);
        DATA_SOURCE.setPassword(password);
    }

    //获取数据库连接
    public static Connection getConnection(){
        Connection conn = CONNECTION_HOLDER.get();
        if(conn == null){
            try {
                conn = DATA_SOURCE.getConnection();
            } catch (SQLException e) {
                LOGGER.error("get connection failure",e);
                throw new RuntimeException(e);
            }finally {
                CONNECTION_HOLDER.set(conn);
            }
        }
        return conn;
    }

    //查询实体列表
    public static <T> List<T> queryEntityList(Class<T> entityClass,String sql,Object...params){
        List<T> entityList;
        try {
            Connection conn = getConnection();
            entityList = QUERY_RUNNER.query(conn,sql, new BeanListHandler<T>(entityClass),params);
        } catch (SQLException e) {
            LOGGER.error("query entity list failure",e);
            throw new   RuntimeException(e);
        }
        return entityList;
    }
    //查询实体
    public static <T> T queryEntity(Class<T> entityClass,String sql,Object...params){
        T entity;
        Connection conn = getConnection();
        try {
            entity = QUERY_RUNNER.query(conn,sql,new BeanHandler<T>(entityClass),params);
        } catch (SQLException e) {
           LOGGER.error("query entity failure",e);
            throw  new RuntimeException(e);
        }
        return entity;
    }

    //执行查询语句
    public static List<Map<String,Object>> executeQuery(String sql,Object...params){
        List<Map<String,Object>> result;
        Connection conn = getConnection();
        try {
            result = QUERY_RUNNER.query(conn,sql,new MapListHandler(),params);
        } catch (SQLException e) {
           LOGGER.error("execute query failure ",e);
            throw new RuntimeException(e);
        }
        return result;
    }

    //执行更新语句
    public static int executeUpdate(String sql,Object...params){
        int rows = 0;
        Connection conn = getConnection();
        try {
            rows = QUERY_RUNNER.update(conn,sql,params);
        } catch (SQLException e) {
            LOGGER.error("execute update failure",e);
            throw new RuntimeException(e);
        }
        return rows;
    }

    //执行插入操作
    public static <T> boolean insertEntity(Class<T> entityClass,Map<String,Object> fieldMap){
        if(CollectionUtil.isEmpty(fieldMap)){
            LOGGER.error("can not insert entity:fieldMap is empty");
            return false;
        }
        String sql = "insert into "+getTableName(entityClass);
        StringBuilder columns = new StringBuilder("(");
        StringBuilder values = new StringBuilder("(");
        for(String fieldName:fieldMap.keySet()){
            columns.append(fieldName).append(", ");
            values.append("?, ");
        }
        columns.replace(columns.lastIndexOf(", "),columns.length(),")");
        values.replace(values.lastIndexOf(", "),values.length(),")");
        sql = sql+columns+" values "+values;
        Object [] params = fieldMap.values().toArray();
        return executeUpdate(sql,params) == 1;
    }

    //更新实体
    public static <T> boolean updateEntity(Class<T> entityClass,long id,Map<String,Object> fieldMap){
        if(CollectionUtil.isEmpty(fieldMap)){
            LOGGER.error("update entity failure:fieldMap is empty");
            return  false;
        }
        String sql = "UPDATE "+getTableName(entityClass)+" SET ";
        StringBuilder columns = new StringBuilder();
        for(String fieldName:fieldMap.keySet()){
            columns.append(fieldName).append("=?,");
        }
        sql+=columns.substring(0,columns.lastIndexOf(","))+" WHERE ID=?";
        List<Object> paramList = new ArrayList<Object>();
        paramList.addAll(fieldMap.values());
        paramList.add(id);
        Object [] params = paramList.toArray();
        return executeUpdate(sql,params) == 1;
    }

    //删除实体
    public static <T> boolean deleteEntity(Class<T> entityClass,long id){
        String sql = "DELETE  FROM "+getTableName(entityClass)+" WHERE ID=?";
        return executeUpdate(sql,id) ==1;
    }

    //执行sql文件中的sql语句
    public static void executeSqlFile(String filePath){
        InputStream is = Thread.currentThread().getContextClassLoader().getResourceAsStream(filePath);
        BufferedReader reader = new BufferedReader(new InputStreamReader(is));
        try {
            String sql;
            while((sql = reader.readLine()) !=null ){
                executeUpdate(sql);
            }
        } catch (IOException e) {
            LOGGER.error("execute sql file failure",e);
            throw new RuntimeException(e);
        }
    }
    //获取表名
    private static String getTableName(Class<?> entityClass){
        return entityClass.getSimpleName();
    }
}
